Hello Akash,

For admission in IIST Candidates must clear the JEE Advanced exam. General category candidates must score at least 20% marks in JEE Advanced i.e 72 marks out of 360 and at least 6 marks out of 120 in each of the three subjects, OBC-NCL candidates must score at least 65 marks out of 360 marks and 5 marks out of 120 in each of the three subjects, SC, ST & PD candidates must score at 10% marks i.e 36 marks out of 360 and 3 marks out of 120 in each of the three subjects

for detailed information and important dates about admission in IIST visit the link given below

https://engineering.careers360.com/articles/iist-btech-admission

hope this information will help you